Geographic Range

Macrosiphum euphorbiae, the potato aphid, is native to North America. It is widespread across the United States and Canada, and the species has spread from the Nearctic region to the Palearctic, Ethiopian, and Neotropical regions. Its range has increased to an almost worldwide distribution, and M. euphorbiae is a significant crop pest. Populations can be found throughout Europe, Asia, Africa, South America, and Australia. (Finlayson, et al., 2009; Le Guigo, et al., 2012; Raboudi, et al., 2011; Stary, et al., 1993; Valenzuela, et al., 2009)

Physical Description

Macrosiphum euphorbiae is considered to be a medium-sized aphid. The species has winged and wingless forms. Apterous (wingless) forms typically are 1.7 to 3.6 mm long, and alate (winged) forms are 1.7 to 3.4 mm long. Macrosiphum euphorbiae is spindle or pear-shaped. It has a soft body; long, dark antennae; and a pair of cornicles at the end of its abdomen. Its color can vary among shades of green, pink, or magenta, while its eyes are reddish. Nymphs resemble smaller adults and often are covered in a grayish-white wax. Apterous adults usually appear shinier than nymphs. (Boquel, et al., 2011; Kaplan and Thaler, 2012; Petrovic-Obradovic, 2010; Stoetzel, 1994; van Emden and Harrington, 2007)

Reproduction

Holocyclic populations of Macrosiphum euphorbiae (where the aphid life cycle includes both parthenogenesis and sexual reproduction) occur only in North America. Anholocyclic populations (in which female aphids reproduce only by parthenogenesis) occur throughout the rest of its global range. Egg-laying females (oviparae) produce a pheromone to attract male mates. The pheromone is produced by a gland on the hind tibia, and the female lifts her legs to release it. (Alyokhin, et al., 2011; Boquel, et al., 2011; Goldansaz and McNeil, 2006)

Holocyclic populations of M. euphorbiae (in which individuals undergo both parthenogenesis and sexual reproduction) are present in North America. In these holocyclic populations, eggs that have overwintered on primary hosts (usually Rosa spp.) hatch in May. In the spring, M. euphorbiae produces several wingless, parthenogenetic generations while colonizing its primary host. Later, winged females are produced; the winged offspring colonize secondary host plants in June and July. Macrosiphum euphorbiae colonizes over 200 secondary host plant species, though it typically prefers plants of the family Solanaceae. Parthenogenesis continues on the secondary host until the fall, at which time males and sexually reproductive females are produced. Males and sexually reproductive females return to the primary host plant species, mate, and lay eggs that overwinter. Anholocyclic populations (in which individuals reproduce only by parthenogenesis) account for the M. euphorbiae populations that are distributed throughout the rest of the world. The life cycle in anholocyclic M. euphorbiae populations is similar, except for the absence of the sexually reproductive stage. Apterous (wingless) females of M. euphorbiae likely overwinter on primary host plants in warmer regions and later produce alate (winged) females that in turn colonize secondary hosts later in the season. One female can give birth to anywhere from a few to 50 offspring in a single day. Macrosiphum euphorbiae nymphs develop to reproductive maturity after about 6 to 12 days. (De Conti, et al., 2011; Lamb, et al., 2009; Raboudi, et al., 2011)

Sexually reproducing populations breed between the end of summer and early fall.

Range age at sexual or reproductive maturity (female)

6 to 12 days

In holocyclic populations of Macrosiphum euphorbiae, eggs are laid on a primary host plant to overwinter, which provides a food source for the offspring when they hatch in the spring. Adults also provision the eggs. Live birth by parthenogenesis is a significant energy investment by the female parent. Because these clones join the colony at birth, interaction with the parent may occur; however, adults provide no parental care. (Macgillivray and Anderson, 1964; van Emden and Harrington, 2007)

Parental Investment

pre-hatching/birth

provisioning

female

pre-weaning/fledging

provisioning

female

Lifespan/Longevity

Behavior

Like all aphids, Macrosiphum euphorbiae lives in large colonies. These colonies can grow to large sizes quickly due to live birth by parthenogenesis (which eliminates the need and time to find a mate) and the relatively quick maturation time of the offspring. Colonies can be established when alate (winged) aphids fly from primary to secondary host plants. However, because aphids are notoriously weak fliers, they often move on air currents and thus have little control over the direction of flight. Flight and any resulting colonization is largely random. Small-scale dispersal can occur when apterous (wingless) aphids walk from one plant to another. Macrosiphum euphorbiae is diurnal. (Boquel, et al., 2011; Narayandas and Alyokhin, 2006; Pompon, et al., 2010a)

Home Range

The home range for Macrosiphum euphorbiae has not been reported, but its range is limited significantly by its poor flight ability. Colonization by alate (winged) forms is determined mainly by air currents. Small-scale dispersal range is determined by the distance that M. euphorbiae individuals can walk, likely only to neighboring plants. (Boquel, et al., 2011; Narayandas and Alyokhin, 2006; Pompon, et al., 2010a)

Communication and Perception

The main sensory organ in aphids is their antennae. The antennae are used for tactile and chemical detection. To determine whether a plant is a suitable host, Macrosiphum euphorbiae uses its antennae to feel along the leaves and detect host-specific odors and other chemical cues. Macrosiphum euphorbiae also uses its stylet mouthparts to probe into plants beneath the epidermis. Color cues can play a role in host plant selection, and M. euphorbiae can detect UV light. In other insects, UV light likely plays a role in flight patterns; however, the detection of UV light by M. euphorbiae likely serves a different purpose, as aphids are weak fliers and instead rely on air currents. Changes in UV light have been shown to alter orientation and colonization in M. euphorbiae. Aphids that are captured or harassed produce an alarm pheromone that alerts other aphids of danger. The alarm pheromone typically elicits evasive behaviors in aphids, such as dropping off the host plant or walking away. In M. euphorbiae, alarm pheromones also cause an increase in the parthenogenetic production of winged individuals, while sexually reproductive females produce a pheromone that attracts male mates. (Goldansaz and McNeil, 2006; Kaplan and Thaler, 2012; Legarrea, et al., 2012; Pompon, et al., 2010a)

Food Habits

Macrosiphum euphorbiae feeds on plant phloem. It uses its stylet mouthparts to pierce the plant tissue and access the phloem. This aphid species is highly polyphagous and has been documented as feeding on over 200 species in 20 different plant families, many of them crop species. Its most notable host plants include plants in the Solanaceae family, particularly potatoes and tomatoes and plants in the Brassicaceae family, including cabbage and lettuce. Macrosiphum euphorbiae individuals (usually dehydrated alate females) also have been observed consuming xylem sap for rehydration. (Atamian, et al., 2013; Le Guigo, et al., 2012; Legarrea, et al., 2012; Pompon, et al., 2010b)

Ecosystem Roles

Macrosiphum euphorbiae is a significant crop pest with an almost worldwide distribution. It colonizes over 200 host plant species. Its primary host often is cited to be Rosa spp. Its preferred secondary host is potato, though M. euphorbiae feeds on other plant species in the family Solanaceae. Other significant host plants include tomatoes, lettuce, and plants in the Brassicaceae family, such as cabbage. All aphids, including M. euphorbiae, contain a bacterial endosymbiont, Buchnera aphidicola. These bacteria live within the bodies of aphids and synthesize amino acids that the aphids cannot get from their nutrient-poor phloem diet. The European red ant, Myrmica rubra, has been documented tending colonies of M. euphorbiae in a mutualistic relationship. The ants eat the honeydew produced by the aphids; in return, the ants protect, clean, and transport the aphids. Macrosiphum euphorbiae is prey to many species of lady beetle and many other insect species, such as syrphid flies and green lacewings. Many species of wasp parasitoids lay eggs inside aphids, which causes aphid death when the wasp offspring hatch. These wasp species can be used to control aphid populations. Aphidius ervi and Praon volucre are two of the major wasp species that use M. euphorbiae as a host. Pathogenic fungi in the genus Entomophthora can cause disease and death in M. euphorbiae. (Alyokhin, et al., 2011; Atamian, et al., 2013; Boquel, et al., 2011; Finlayson, et al., 2009; Francis, et al., 2010; Le Guigo, et al., 2012; Legarrea, et al., 2012; Lins, et al., 2013; Petrovic-Obradovic, 2010; Thi, et al., 2013)

Economic Importance for Humans: Positive

There are no known positive effects of Macrosiphum euphorbiae on humans.

Economic Importance for Humans: Negative

Macrosiphum euphorbiae, the potato aphid, is described as one of the most harmful aphid species in the world. It feeds on many plant species and causes significant crop damage in potatoes, tomatoes, lettuce, and cabbage. The aphid also is a vector of many plant diseases, including 40 non-persistent viruses and several persistent viruses (e.g., yellow net virus, pea leaf roll virus, and potato leaf roll virus). To prevent as much crop damage as possible, substantial research has been and continues to be conducted to find the most effective insecticides, biological control methods, and resistant plants. (Legarrea, et al., 2012; Raboudi, et al., 2011; van Emden and Harrington, 2007)

Contributors

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

Neotropical

living in the southern part of the New World. In other words, Central and South America.

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

agricultural

living in landscapes dominated by human agriculture.

asexual

reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

diurnal

active during the day, 2. lasting for one day.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parthenogenic

development takes place in an unfertilized egg

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic.
Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Stoetzel, M. 1994. Aphids (Homoptera: Aphididae) of potential importance on citrus in the United States with illustrated keys to species. Proceedings of the Entomological Society of Washington, 96/1: 74-90.

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This material is based upon work supported by the
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Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.